Ultrasonic surgical shears are known which include an ultrasonic surgical blade, a clamping arm operable to open and close toward the blade, and a polytetrafluoroethylene tissue pad which is attached to the clamping arm and which includes a clamping surface. The clamping arm exerts a clamping force on a blood vessel which is positioned between the clamping surface of the tissue pad and the blade. Exemplary devices are described in U.S. Pat. Nos. 5,322,055 and 6,325,811, the contents of which are incorporated herein by reference. The result of the ultrasonically-vibrating ultrasonic surgical blade and the clamping force on the blood vessel is a coaptation of the blood vessel (a bringing together of the walls of the blood vessel), a transection (a cutting) of the coaptated blood vessel, and a coagulation (a sealing) of the coaptated cut ends of the blood vessel.
Still, scientists and engineers continue to seek improved ultrasonic surgical instruments and methods.